Subcutaneous versus endovenous trastuzumab: Real world data from a reference cancer center in Peru.
Authors: Iris Otoya, Natalia Valdivieso, Katia Roque, Zaida Morante, Tatiana Vidaurre, Silvia P. Neciosup, Henry Leonidas Gomez
Journal: Journal of Clinical Oncology (2023)

e12527 Background: HER2 receptor amplification/overexpression is identified in approximately 20% of invasive breast neoplasms; it is characterized by biologically aggressive behavior and worse prognosis compared to HER2-negative tumors. Trastuzumab, a humanized monoclonal antibody, was approved for therapeutic use in HER2-positive breast cancer. The objective of this study is to compare the acquisition costs, costs, and preparation and application times of trastuzumab presentations. Methods: Descriptive and retrospective study in female patients aged 18 years and older with a diagnosis of HER 2 positive early breast cancer who received subcutaneous or intravenous trastuzumab during the years 2019-2021. The study setting was the National Institute of Neoplastic Diseases (INEN)- Lima/Peru. We created a simple spreadsheet model to evaluate costs (expressed in soles). The analysis included the calculation of patient time in the chemotherapy chair, preparation time and treatment administration time. Results: The cost of the subcutaneous presentation was S/4212 and S/4348 for the intravenous presentation. The cost of the complete treatment was S/75816 for the subcutaneous presentation and S/82612 for the intravenous presentation. The cost of the supplies used in the preparation of 18 cycles of treatment for the subcutaneous presentation was S/ 20.7 and for the intravenous presentation S/ 399.96; likewise, the cost of the supplies used in the administration of 18 cycles of treatment for subcutaneous trastuzumab was S/ 34.02 and for the intravenous presentation was S/ 1094.4. The cost of using a chemotherapy chair for 18 cycles for subcutaneous presentation was S/36 and for intravenous presentation S/663. The time used in the application of 1 cycle of subcutaneous presentation was 30 minutes for the first application and 15 minutes for subsequent applications; the time used in the application of each cycle for endovenous presentation was 6 hours for the first application and 2 hours for subsequent applications. The administration of 18 cycles for subcutaneous presentation was S/ 732.45 and for intravenous presentation S/ 6168. The trastuzumab formulation for subcutaneous application is a ready-to-use solution, so it did not generate preparation costs. The preparation time for one cycle of intravenous presentation was 15 minutes and meant an investment of S/693.90 for the preparation of 18 cycles (cost of preparation personnel time). Conclusions: The use of subcutaneous trastuzumab generates less costs associated with an overall savings of 16.36%, its use implies less time for preparation and application, as well as a reduction in patient chair time. These time reductions translate into economic savings, a more efficient use of resources and a reduction in waiting time for appointments in the chemotherapy service and a greater capacity of the oncology service to treat a greater number of patients.